Safety latch for doors,windows,and the like



H. s. CARLSTON 3,458,226

SAFETY LATCH FOR DOORS, WINDOWS, AND THE LIKE 2 Sheets-Sheet 1 July 29,1969 Filed April (5. 1967 HAM/LTUN S. CARLSTDN INVEN TOA jaw/7 M.

July 29, 1969 s CARLSTON 3,458,226

SAFETY LATCH FOR DOORS, WINDOWS, AND THE LIKE Filed April 6, 1967 2Sheets-Sheet 2 27 606 IR 58 8 64: 6R H65 36 A TTORNEYS United StatesPatent 3,458,226 SAFETY LATCH FOR DOORS, WINDOWS, AND THE LIKE HamiltonS. Carlston, 1923 Fresno St., Fresno, Calif. 93721 Filed Apr. 6, 1967,Ser. No. 629,002 Int. Cl. Ec 17/16, 17/28 U.S. Cl. 292268 2 ClaimsABSTRACT OF THE DISCLOSURE A safety latch having an axially positionablebolt mounted in a closure for selective releasable sliding connectionthrough a slotted strap mounted on a frame for the closure limitingmovement of the closure away from the frame to a partially openedposition. The bolt is releasable from the strap to permit full openingof the closure only after the closure is returned to a fully closedposition against the frame thus imparting a significant safety advantageto the latch.

Background of the invention Safety chain latches have long been employedon doors and the like to permit partial opening of the doors forventilating purposes, inspection of callers, and the like.

Ordinarily, if installed correctly, the chain latch cannot be removeduntil the door is fully closed. Such chain latches, however, are notcompletely burglar-proof. If the door is opened only a slight amount, arelatively thin tool can be inserted through the opening to unlatch thechain. Furthermore, such chains are mounted in a continuously exposedposition on the door frames which present an unsightly appearance andcreate some hazard to people passing through the doorway. These chainlatches have not been readily adapted or accepted for use on slidingwindows and other similar closures primarily because of theinconvenience involved in their use and their unsightly appearance.Furthermore the chain latches require an additional procedure whenlocking or unlocking the closure in that the fastener member on the endof the chain must be removed from the mounting bracket on the frame andslipped into the bracket on the door.

Accordingly, it is an object of the present invention to provide animproved safety latch for closures such as doors, windows and the like.

Another object is to provide an improved safety latch which isautomatically actuated during the normal opening and closing proceduresinvolving an associated door, window or the like.

Another object is to provide a safety latch of the character describedwhich is substantially completely hidden when the closure is disposed ina closed position.

Another object is to provide an improved safety latch which is capableof constraining the closure in a partially opened position and which isnot releasable until the closure is returned to its fully closedposition.

Another object is to provide an improved safety latch which isconveniently installed, is economically produced, and is virtuallyburglar-proof.

Other objects and advantages of the present invention will subsequentlybecome more clearly apparent upon reference to the following description.and accompanying drawings.

Brief description of the drawings position and a partially openedlatched dashed line position.

FIG. 2 is a somewhat enlarged fragmentary front elevation of a slottedstrap utilized by the safety latch of the present invention shown in afull line depending position aligned with the door frame when the dooris closed and in an upwardly swung dashed line position when the door isdisposed in its partially opened latched position.

FIG. 3 is a somewhat enlarged transverse vertical section, taken on line3-3 of FIG. 1, through a turnbolt utilized by the present inventionwhich is disposed within the door in adjacent relation to the strap ofFIG. 2 when the door is closed.

FIG. 4 is a somewhat enlarged longitudinal vertical section, taken online 44 of FIG. 1, showing the turnbolt disposed in a door lockingposition through the strap on the frame.

FIG. 5 is a somewhat enlarged horizontal longitudinal section, taken online 5-5 of FIG. 4, showing the turnbolt in an intermediate full linedoor latching position and a fragmentary dashed line position with thedoor in its partially opened position.

FIG. 6 is a fragmentary front elevation showing a modified form of thepresent invention .adapted for use on a sliding window.

FIG. 7 is a transverse vertical section, taken on line '77 of FIG. 6,showing the safety latch in a window locking position.

Description of the preferred embodiments Referring more particularly tothe drawings, a safety latch embodying the principles of the presentinvention is generally indicated by the reference numeral 10. The safetylatch is associated with a substantially upright door 11 mounted forpivotal swinging movement within a substantially rectangular door frame12 on a plurality of hinges, one of which is indicated at 14. The doorincludes an outer side edge 16 adjacent to which is mounted aconventional doorknob and main key latch set generally indicated by thereference numeral 18. The frame includes an elongated door bumper stripor stop 20 for positioning the door in closed relation within the frame.As best shown in FIGS. 4 and 5, the frame also provides a bore 22 inaligned relation with the safety latch 10 on the door.

As best shown in FIG. 2, the safety latch 10 provides an elongated strap25 of substantially rigid, preferably hardened sheet steel material. Thestrap includes a mounting end 26 which is pivotally connected to asubstantially rectangular mounting plate 27 in predetermined spacedsubstantially parallel relation by a rivet 28 and a spacer washer 29.The mounting plate is morticed into a recess in the edge of the frameopposite to the edge of the door 11 and is constrained in such positionby a plurality of wood screws 30 having countersunk slotted heads 32disposed in spaced ordered arrangement in the plate. The.

mounting end 26 of the strap has a plurality of arcuate notches 34 and acorresponding arcuate protuberance 35 adjacent to one of the notches. Asbest shown in FIG. 2, the notches are positioned so as to expose theupper screw heads 32 for installing the strap on the frame in its fullline depending position. It will be noted that when the strap is swungupwardly to the dashed line position of FIG. 2, the screw heads arecovered by the mounting end of the strap and by the protuberance 35. Thestrap further in cludes a circular bore 36 therethrough which, in theposition shown in FIG. 2, is aligned with a corresponding bore -37 inthe mounting plate and with the bore 22 in the frame 12. An elongatedslot 38 of a width somewhat smaller than the diameter of the bores 36and 37 is formed in the strap and provides an opposite closed end 39.

The safety latch 10 further includes a turnbolt assembly generallyindicated by the reference numeral 45, which is mounted adjacent to theouter edge 16 of the door 11. The turnbolt assembly provides anelongated tubular barrel 46 which is rigidly mounted within a bore 47formed in the outer edge 16 of the door. An elongated bolt 50 is axiallyslidably disposed within the barrel and has an elongated notch 52providing therein a toothed rack segment 54. A turnknob 56 is rotatablysecured to the face of the door 11 by a screw-mounted escutcheon plate57. The turnknob has an inwardly extended splined pinion end 58 disposedin meshing relation with the toothed rack 54 of the bolt.

The bolt 50 further includes an elongated plunger 60 slidably disposedwithin a bore 62 therein which terminates short of the notch 52. Theplunger is of a diameter slidably to be received within the slot 38 ofthe safety strap 25. The plunger has an outer circular head 64 which isdisposed in predetermined axially spaced relation to the outer end ofthe bolt when the plunger is inwardly disposed against the bottom of thebore 62 to form an annular groove 65. The plunger includes an elongatedslot 66 through which is transversely extended a retaining pin 67 havingopposite ends rigidly mounted in the barrel 46. A compression spring 68is mounted within the plunger between its inner end and the pinproviding a force normally urging the plunger to its retracted positionwithin the bolt.

Operation of the first form The operation of the first form of thesubject invention is believed to be clearly apparent and is brieflysummarized at this point. With the door 11 disposed in its closedposition of FIG. 1, the turnknob 56 is rotatably manipulated to extendthe bolt to the right, as viewed in FIG. 4. Such movement extends thebolt through the circular bores 36 and 37 in the strap 25 and themounting plate 27, respectively, and into the bore 22 of the door frame12, thereby locking the door in its closed position relative to theframe. Upon rotation of the knob 56 in the opposite direction, the boltis retracted inwardly into the barrel 46 to a fully concealed positionwith the head 64 of the bolt disposed flush with the outer edge 16 ofthe door. It is obvious that with the bolt in its maximum retractedposition, the door 11 can be swung to its fully opened position withoutrestriction.

The knob 56 may be rotated from either of the above described maximumextended and retracted positions to an intermediate setting to disposethe annular groove 65 formed between the head 64 of the plunger 60 andthe outer end of the bolt 50 in alignment with the plane of the strap25. Accordingly, when the door 11 is swung toward its opened position,the plunger 60 is carried along the slot 38 for longitudinal slidingmovement toward the closed end 39 of the slot. During such movement, thestrap is pivoted about the rivet 28 and is swung upwardly by suchoutward swinging movement of the door from the frame. As the strapapproaches the dashed line position of FIG. 2, the arc of the doorcauses the edge 16 of the door to move somewhat away from the strap 25.This movement is accommodated by compression of the spring 67 andextension of the plunger 60 outwardly from the bolt 50, as shown in FIG.5. Such outward swinging movement of the door is terminated uponengagement of the plunger with the closed end 39 of the slot 38dependably to hold the door in a partially opened position. Aspreviously noted, with the strap 25 disposed in its upwardly swungdashed line position of FIG. 2, the screw heads 32 are covered by themounting end 26 of the strap to preclude removal of the screws when thedoor is disposed in the described partially opened position.

If it is desired that the door be swung to its fully opened position,the safety latch requires that the door be first returned to its fullyclosed position wherein the bores 36, 37 and 22 are aligned for freeaxial movement of the bolt 50. The turn knob 56 is then rotated in theappropriate direction fully to retract the bolt into the barrel 46 andfor retraction of the head portion 64 of the plunger 60 from thecircular bores 36 and 37 in the strap 25 and the plate 27, respectively.If the turn knob is left in its intermediate safety latching position,the described movement of the plunger 60 through the slot 38 in thestrap is automatically effected during each successive opening andclosing of the door. Accordingly, the safety latch remains in operationuntil the turn knob is positioned for either locking the door byextension of the bolt into the bore 22 within the door frame 12 or thebolt is retracted into the door so as to enable the door to be fullyopened but only from its fully closed position.

Second form A second form of the safety latch of the present inventionis shown in FIGS. 6 and 7. In this form, a safety latch generallyindicated by the reference numeral 80, which is substantially identicalto the safety latch 10 of the first form, is adapted for use on asliding window 82. The window provides a sash 83 having opposite sides,one of which is shown at 84, and opposite upper and lower portions, thelatter of which is indicated at 85. The lower sash portion has anelongated downwardly opening recess 88 and is disposed for horizontalsliding movement within a window frame 90 providing a lower track 92. Abore 93 is formed within the lower sash portion beneath the side portion84 of the window sash disposed in the closed position of FIG. 6.

The safety latch 80 is mounted in the side portion 84 of the sash 83 andincludes an elongated barrel having a bolt 102 axially slidably disposedtherein. The bolt is actuated by a turn knob 104 having an inwardlyextended splined pinion end 105 extended through the bolt in meshingrelation with a toothed rack segment 106. As in the first form, the knobis rotatably constrained in such position on the window sash by anescutcheon plate 108 having a plurality of screws 109 extended into thesash. The bolt 102 includes a head portion 111 which is extendible intothe bore 93 of the frame in order to lock the window in the closedposition. An annular groove 114 is formed in the bolt closely adjacentto the head 111 to provide a reduced diameter portion 115.

An elongated safety strap having a circular bore 122 and an elongatedslot 124 having a closed end 125 identical to the strap 25 of the firstform is mounted within the track 92 of the frame by a mounting plate126. The plate has a circular bore 127 aligned with the bore 122 in thestrap and with the bore 93 in the frame. The bores are of a diameterpermitting free movement of the bolt 102 therethrough and into therecess. It is noted that in such sliding window installation, the strap120 need not be pivotally mounted on the plate 126 and the spring 67 andplunger 60 within the bolt 50 of the first form are not required.

Operation of the second form The operation of the second form issubstantially identical to the operation of the first form in that thebolt 102 is manipulatable by the knob 104 to three positions permittinglocking of the window in its closed position, movement of the window toits fully opened position, and an intermediate partially latchedposition. It is apparent that the bolt is only manipulatable with thewindow disposed in its closed position of FIG. 6 wherein the bolt isfree to be axially shifted to any one of the three above describedpositions. In order to limit movement of the window to its partiallyopened position, the knob is actuated to lift the bolt upwardly withinthe window sash to a position aligning the groove 114 in the bolt withthe elongated slot 124 in the strap. The window may then be slid to theleft, as viewed in FIG. 6, during which time the reduced diameterportion 115 of the bolt is permitted to slide through the elongated slotuntil abutting the opposite closed end 125 thereof.

It is further apparent that with the sliding connection provided betweenthe groove 114 and the slot 124, the bolt is precluded axial movementuntil the window sash is returned to its closed position and the boltagain aligned with the circular bores 122 and 127 in the strap andplate, respectively.

In view of the foregoing, it is readily apparent that the structure ofthe present invention provides an improved safety latch for doors,windows and the like which is capable of restraining the closure in apartially opened position and which is not releasable until the closureis returned to its fully closed position. The safety latch is virtuallyburglar-proof in that all the mounting screws are covered by portions ofthe latch when the closure is disposed in its partially opened position.Furthermore, with the exception of the actuating knob, the safety latchis completely hidden from view by the elimination of the externallymounted chain or strap structures of the prior art.

Although the invention has been herein shown and described in what areconceived to be the most practical and preferred embodiments, it isrecognized that departures may be made therefrom within the scope of theinvention.

Having described my invention, what I claim as new and desire to secureby Letters Patent is:

1. A safety latch, for a pair of members mounted for relative spacialmovement, comprising a planar substantially rigid limit strap having aslot and being pivotally mounted on one of said members for movementbetween retracted and extended positions; and a slidable bolt mounted onthe other of said members having a head with a reduced portion slidablyreceived in the slot of the strap, said head being telescopicallymounted within the bolt,

stop means within the bolt, and a compression spring disposed betweensaid stop means and the head urging said head toward a retractedposition within the bolt and permitting extensible outward travel of thehead to accommodate movement of said other member away from the strap asthe head travels along the slot.

2. A safety latch, for a closure pivotally mounted in a closure frameand having a predetermined swinging path of movement between open andclosed positions with said latch permitting partial opening of theslosure but precluding full opening from such partially opened positionuntil after first fully closing the same, 'comprising a planarsubstantially rigid strap having an inner end pivotally mounted on theframe and an outer end swingable outwardly from the frame in adjacentrelation to the path of movement of said closure to and from said closedposition, said strap having an elongated longitudinal slot thereinproviding a circular bore at the inner end thereof of a diametersomewhat larger than the width of the slot and an opposite closed end;an axially adjustable bolt mounted in the closure substantially radiallythereof for extension through said circular bore in the strap when theclosure is substantially in its closed position with the bolt having anelongated axial bore; an elongated plunger having an inner portionslidably fitted to said bore in the bolt and an outer portion outwardlyextended from the bore for sliding movement through said slot of thestrap and including a flanged head disposable through said circular boreand slidably engageable with the side of the strap opposite to said boltfor engagement with said closed end of the strap for limiting movementof the closure to said partially open position, said plunger having anelongated axial slot; a stop pin mounted in the bolt and transverselyextended through the slot in the plunger to limit inward movement of theplunger into said bolt; and a compression spring disposed within saidslot in the plunger between said stop pin and the opposite end of theslot adjacent to said inner end of the bolt normally to urge the plungertoward a retracted position within the bolt but being compressible topermit outward extendible movement of the plunger to accommodate arcuateswinging movement of the closure away from the strap incident tomovement of the plunger through the slot in the strap during movement ofthe closure between its closed and its partially open positions.

References Cited UNITED STATES PATENTS 1,673,189 6/1928 Frank 292-2682,010,461 8/1935 Milligan 70143 2,369,136 2/1945 Chambers 292-2682,704,684 3/ 1955 Kleinemeier -a 292-268 388,074 8/1888 Reardon 2922692,030,916 2/1936 Gard 292269 FOREIGN PATENTS 322,971 7/ 1920 Germany.

MARVIN A. CHAMPION, Primary Examiner E. I. McCARTHY, Assistant Examiner

